The importance of urban rainwater harvesting in circular economy: the case of Guadalajara city

Purpose - This paper aims to associate two fields of research: circular economy and the restoration of water cycle through the implementation of rainwater catchment systems in urban zones. Design/methodology/approach - This study considers the case of the metropolitan zone of Guadalajara, México. This urban concentration is the second largest in Mexico. It faces floods each year with a cost of over US$26m, while demand of water has a production cost over US$24m. At the same time, the aquifers are drying due to uncontrolled urbanization and increasing the impervious area over the recharge zones. In addition, rainwater is combined with wastewater, elevating the cost of the wastewater treatment because the amount and quality of water to treat exceeds the systems’ capacity. This situation causes floods and decreases the availability of ground water. These problems are reflected in the imbalance of parameters of water cycle and a new approach is needed. The circular economy model can help to preserve one of our most vital resources. Scarcity is already so pronounced that we cannot reach many of our desired economic, social and environmental goals. Technologies that help balance supply and demand can also help water (both stock and flow) to become part of a circular model. To prove this, the authors present a hypothetical scenario based on a pilot project and a basin modeling of Guadalajara, Mexico. Findings - Through this paper, it is possible to demonstrate that rainwater harvesting can play an important role in circular economy. Using the rainwater catchment systems, the cost of damages caused by floods could be decreased, the demand of water could be reduced, cost of production can be reduced, the aquifers can be recharged and the wastewater treatments can be improved. Originality/value - Few papers have been developed to associate two fields of research (circular economy and the restoration of water cycle), using rainwater catchment systems as the central element.